Disk drive with a housing hole seal including a conductive layer with an exposed planar surface region

ABSTRACT

A disk drive includes a disk drive housing having a hole therethrough. A disk is enclosed within the disk drive housing, and is rotatably attached to the disk drive housing. A seal covers the hole through the disk drive housing. The seal includes a conductive layer, a primary dielectric layer, and a gasket layer. The conductive layer has a covered surface region and an exposed planar surface region. The exposed planar surface region is lacking a dielectric coating disposed thereon. The primary dielectric layer includes an adhesive coating disposed between the primary dielectric layer and the covered surface region. The gasket layer includes first and second adhesive gasket layer sides and a gasket opening disposed through the gasket layer. The gasket opening is disposed about the hole in the disk drive housing, with the first adhesive gasket layer attached to the disk drive housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending U.S. patent applicationSer. No. 12/651,944, entitled “Disk Drive Housing Hole Seal Including aConductive Layer with an Exposed Planar Surface Region,” filed on Jan.4, 2010, now U.S. Pat. No. 8,530,032 B1, which is itself a continuationof now-granted U.S. patent application Ser. No. 11/607,716, filed onDec. 1, 2006, now U.S. Pat. No. 7,709,078, issued on May 5, 2010, all ofwhich are hereby incorporated by reference in their entireties.

BACKGROUND

The typical hard disk drive includes a head disk assembly (HDA) and aprinted circuit board assembly (PCBA) attached to a disk drive base ofthe HDA. The head disk assembly includes at least one disk (such as amagnetic disk, magneto-optical disk, or optical disk), a spindle motorfor rotating the disk, and a head stack assembly (HSA). The printedcircuit board assembly includes a servo control system in the form of adisk controller for generating servo control signals. The head stackassembly includes at least one head, typically several, for reading andwriting data from and to the disk. In an optical disk drive, the headwill typically include a mirror and objective lens for reflecting andfocusing a laser beam on to a surface of the disk. The head stackassembly is controllably positioned in response to the generated servocontrol signals from the disk controller. In so doing, the attachedheads are moved relative to tracks disposed upon the disk.

A hole may be formed through the disk drive base. The hole may beutilized to provide access to the disk once the disk drive is assembled.For example, the disk may be accessed for writing servo control dataonto the disk. In order to prevent contamination from entering the diskdrive a seal is disposed over the hole. The seal typically includes ametal layer that is attached to the disk drive base with a pressuresensitive adhesive. The metal layer is used to block particulate matterand also serves as a vapor barrier.

The action of peeling a flexible planar insulative layer off a planarsurface may cause the insulative layer to become charged with onepolarity while the planar surface would attain a potential of oppositepolarity. This phenomenon is called tribocharging ortriboelectrification. As such, static electricity may be generatedduring the removal of a seal from its backing just prior toinstallation. Static electricity may also be generated during removal ofa seal from the disk drive housing. Because the surfaces are insulative,these charges may not be dissipated and have the possibility to build toan eventual undesirable discharge. Such a discharge can damage sensitiveelectrical components within a disk drive.

Accordingly, it is contemplated that there is need in the art for a sealfor use with a disk drive housing hole that is more likely to mitigateelectrostatic discharge events.

SUMMARY

A disk drive includes a disk drive housing having a hole therethrough. Adisk is enclosed within the disk drive housing, and is rotatablyattached to the disk drive housing. A seal covers the hole through thedisk drive housing. The seal includes a conductive layer, a primarydielectric layer, and a gasket layer. The conductive layer has a coveredsurface region and an exposed planar surface region. The exposed planarsurface region is lacking a dielectric coating disposed thereon. Theprimary dielectric layer includes an adhesive coating disposed betweenthe primary dielectric layer and the covered surface region. The gasketlayer includes first and second adhesive gasket layer sides and a gasketopening disposed through the gasket layer. The gasket opening isdisposed about the hole in the disk drive housing, with the firstadhesive gasket layer attached to the disk drive housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded top perspective view of a disk drive including adisk drive housing and a seal according to an embodiment of the presentinvention;

FIG. 2 is a bottom perspective view of a disk drive with a cover and aseal exploded away from the disk drive according to an embodiment of thepresent invention;

FIG. 3 is an enlarged exploded top perspective view of a seal accordingto an embodiment of the present invention;

FIG. 4 is an enlarged exploded bottom perspective view of a sealaccording to an embodiment of the present invention;

FIG. 5 is a top plan view of a seal according to an embodiment of thepresent invention;

FIG. 6 is a bottom plan view of a seal according to an embodiment of thepresent invention;

FIG. 7 is an enlarge side view of a portion of a seal as being partiallyremoved from a disk drive housing;

FIG. 8 is an enlarged exploded top perspective view of a seal accordingto an embodiment of the present invention;

FIG. 9 is an enlarged exploded bottom perspective view of a sealaccording to an embodiment of the present invention;

FIG. 10 is a top plan view of a seal according to an embodiment of thepresent invention; and

FIG. 11 is a bottom plan view of a seal according to an embodiment ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1 there is depicted an exploded top perspectiveview of a disk drive 10 suitable for use with an embodiment of thepresent invention. The disk drive 10 includes a head disk assembly (HDA)12 and a printed circuit board assembly (PCBA) 14. The head diskassembly 12 includes a disk drive housing 16 having disk drive housingmembers, such as a disk drive base 18 and a cover 20. The disk drivebase 18 and the cover 20 collectively house disks 22, 24. A single diskor additional disks may be utilized. Each of the disks 22, 24 includes aplurality of tracks for storing data. Each of the disks 22, 24 may be ofa magnetic recording type of storage device, however, other arrangementssuch as optical recording may be utilized. The head disk assembly 12further includes a spindle motor 26 for rotating the disks 22, 24. Thehead disk assembly 12 further includes a head stack assembly 28rotatably attached to the disk drive base 18 in operable communicationwith the disks 22, 24. The head stack assembly 28 includes an actuator30.

The actuator 30 includes actuator arms 32 (for ease of illustration onlythe topmost one is labeled). Distally attached to the actuator arms 32are suspension assemblies that respectively support heads 34 (for easeof illustration only the topmost one is labeled). The suspensionassemblies with the heads 34 are referred to as head gimbal assemblies.It is contemplated that the number of actuator arms and suspensionassemblies may vary depending upon the number of disks and disk surfacesutilized.

Each head 34 typically includes a transducer for writing and readingdata. Each transducer typically includes a writer and a read element. Inmagnetic recording applications, the transducer's writer may be of alongitudinal or perpendicular design, and the read element of thetransducer may be inductive or magnetoresistive. In optical andmagneto-optical recording applications, the head may also include anobjective lens and an active or passive mechanism for controlling theseparation of the objective lens from a disk surface of a given one ofthe disks 22, 24. Each of the disks 22, 24 includes opposing disksurfaces. In magnetic recording applications the disk surface typicallyincludes one or more magnetic layers. Data may be recorded along dataannular regions on a single disk surface or both.

The head stack assembly 28 may be pivoted such that each head 34 isdisposed adjacent to various data annular regions of the disks 22, 24.The head stack assembly 28 is disposed in electrical communication withthe printed circuit board assembly to facilitate electrical signalsbetween the heads 34 and the printed circuit board assembly 14.

The disk drive housing 16 includes a hole 36. In this embodiment, thehole 36 is disposed through the disk drive base 18. As will be discussedin further detail below, the disk drive 10 may further include a seal38. The hole 36 may be utilized to provide access to the disk 24 oncethe disk drive 10 is assembled. For example, the disk 24 may be accessedfor writing servo control data onto the disk 24. FIG. 2 is a bottomperspective view of the disk drive 10 with the cover 20 and the seal 38exploded away from the disk drive 10. In order to prevent contaminationfrom entering the disk drive a seal 38 is disposed over the hole 36.However, it is desirable to mitigate electrostatic discharge eventsshould the seal 38 ever be removed. This may be the case where the diskdrive 10 requires rework of its internal components.

Referring additionally to FIGS. 3 and 4, there are respectively depictedenlarged exploded top and bottom perspective views of the seal 38. FIGS.5 and 6 respectively depict top and bottom plan views of the seal 38.

The seal 38 includes a conductive layer 40, a primary dielectric layer42, and a gasket layer 44. The conductive layer 40 has a covered surfaceregion 46 and an exposed planar surface region 48. The exposed planarsurface region 48 is lacking a dielectric coating disposed thereon. Theprimary dielectric layer 42 includes an adhesive coating 50 disposedbetween the primary dielectric layer 42 and the covered surface region46. The gasket layer 44 includes first and second adhesive gasket layersides 52, 54 and a gasket opening 56 disposed through the gasket layer44.

In certain embodiments, the conductive layer 40 is disposed between theprimary dielectric layer 42 and the gasket layer 44 such as depicted inFIGS. 3-6. The primary dielectric layer 42 has a first and secondprimary dielectric layer sides 58, 60. The conductive layer 40 has firstand second conductive layer sides 62, 64. The adhesive coating 50 isdisposed at the first primary dielectric layer side 58. As such, thefirst primary dielectric layer side 58 is attached to the secondconductive layer side 64 with the adhesive coating 50. In the embodimentof FIG. 4, the seal 38 further includes a secondary dielectric layer 66.The secondary dielectric layer 66 is disposed between the conductivelayer 40 and the gasket layer 44. The secondary dielectric layer 66 hasfirst and second sides 68, 70. The secondary dielectric layer 66 mayinclude an adhesive coating 72 between the secondary dielectric layer 66and the conductive layer 40. The adhesive coating 72 is disposed at thesecond side 70. As such, the second side 70 is attached to the firstconductive layer side 62 with the adhesive coating 72.

In certain embodiments, the primary dielectric layer 42 may be attachedto the secondary dielectric layer 66 via the intermediate disposition ofthe conductive layer 40. Further, the primary dielectric layer 42 may beattached to the second adhesive gasket layer side 54. In the embodimentof FIG. 4, the primary dielectric layer 42 is attached to the secondadhesive gasket layer side 54 via the intermediate disposition of thesecondary dielectric layer 66 and the conductive layer 40.

The primary dielectric layer 42 may have a primary dielectric layeropening 74. In the embodiment depicted, the primary dielectric layer 42has a plurality of primary dielectric layer openings, individuallylabeled 74 a-c. The primary dielectric layer openings 74 a-c may be of avariety of shapes, geometries and locations, such as the holes throughthe primary dielectric layer 42 depicted in this embodiment. The exposedplanar surface region 48 may be aligned within the primary dielectriclayer opening 74. In the embodiment of FIG. 4, the exposed planarsurface region 48 includes a plurality of sections, individually denoted48 a-c. Respective ones of the sections 48 a-c may be aligned within theprimary dielectric layer openings 74 a-c.

The conductive layer 40 may comprise a variety of materials such as ametal (e.g. aluminum, stainless steel, copper). The conductive layer 40may take the form of a thin sheet of material. The conductive layer 40may be formed through a stamping process.

The primary and secondary dielectric layers 42, 66 may comprise apolymer material. In this regard, the primary and secondary dielectriclayers 42, 66 may be adhesive tape comprising a thin sheet of polymermaterial with a pressure sensitive adhesive disposed upon one or both ofits sides.

The gasket layer 44 may comprise a laminated adhesive material. Thegasket layer 44 may be a double sided adhesive tape comprising a thinsheet of polymer material with pressure sensitive adhesive disposed uponboth sides.

The gasket opening 56 is sized to be disposed about the hole 36 of thedisk drive housing 16. The first adhesive gasket layer side 52 isdisposed about the hole 36 upon the disk drive base 18. The adhesivenature of the first adhesive gasket layer side 52 facilitates attachmentof the seal 38 to the disk drive base 18.

The primary dielectric layer 42, the conductive layer 40, the secondarydielectric layer 66, and the gasket layer 44 may have a variety ofthicknesses. For example, the primary dielectric layer 42 may have athickness between 13 and 250 microns. The conductive layer 40 may have athickness between 20 and 50 microns. The secondary dielectric layer 66may have a thickness between 13 and 250 microns. The gasket layer 44 mayhave a thickness between 35 and 220 microns. Moreover, each of theprimary dielectric layer 42, the conductive layer 40, the secondarydielectric layer 66, and the gasket layer 44 may have uniform ornon-uniform thickness. In addition, such layers may be of a variety ofshapes.

Referring now to FIG. 7 there is depicted a cross sectional side view ofa portion of the seal 38 as being peeled away from the disk drive base18. In this embodiment, the disk drive base 18 may be provided with aninsulative surface coating. Such a peeling action throughtriboelectrification may result in the generation of charges in andabout the seal 38. Positive charges may develop at the surface of thedisk drive base 18 where the seal 38 has been peeled away. Oppositepolarity charges (negative charges in this example) are generated upon asurface of the first adhesive gasket layer side 52. Because theconductive layer 40 is disposed between two insulative layers (theprimary and secondary dielectric layers 42, 66) charge separation occursin the conductive layer 42. Note that within conductive material such asa metal, charges (electrons) are able to move relatively freely. Priorto the peeling action, it can be assumed that the conductive layer 42 isrelatively electrically neutral. However, with the generation of thecharges at the first adhesive gasket layer side 52 adjacent thesecondary dielectric layer 66, positive charges are attracted towardsthe secondary dielectric layer 66 while negative charges are repelled.

The positive charges in the conductive layer 40 become held in anelectric field created by the negative charges in the secondarydielectric layer 66 (such charges in this state are referred to asimmobile charges). The negative charges in the conductive layer 40,however, are relatively free to move (such charges in this state arereferred to as mobile charges).

If the peeling action of the seal 38 were to simply continue until theseal 38 is removed, just prior to separation from the disk drive base 18the seal 38 would have the edge of the conductive layer 40 exposedtowards the disk drive base 18. The electric potential differencebetween the seal 38 (which would carry a negative charge) and the diskdrive base 18 (which would carry a neutral or positive charge) maybecome large enough that negative charges in the conductive layer 40jump the air gap between the seal 38 and the disk drive base 18 causingan electrostatic discharge event.

The exposed planar surface region 48 provides a contact for anelectrical connection to the conductive layer 40. During the peelingaction of the removal process of the seal 38 from the disk drive base18, a grounded person (e.g. factory worker) or tool can be utilized tomake electrical contact with the exposed planar surface region 48 toallow the mobile charges (negative charges in this example) to bedrained away to ground. This would mitigate an electrostatic dischargeevent due to a build up of mobile charges. As such, the configuration ofthe seal 38 facilitates a path to ground to drain charges from theconductive layer 40 so as to avoid an undesirable electrostaticdischarge.

It is noted that in an embodiment where there is no secondary dielectriclayer 66 utilized between the conductive layer 40 and the gasket layer44, the configuration of the electrical charges would be expected to besimilar to that as present in the embodiment shown in FIG. 7.

It is further noted that in an embodiment where the disk drive base 18does not have any insulative coating as is conductive in nature, theconfiguration of the electrical charges would be similar to that aspresent in the embodiment shown in FIG. 7 however with a slightdifference. In this regard, the positive charges of the disk drive base18 would be more evenly dispersed throughout the disk drive base 18rather than gathered at the surface.

Referring now to FIGS. 8-11, there is provided a seal 76 of anotherembodiment. The seal 76 includes a primary dielectric layer 78, aconductive layer 80, and a gasket layer 82. In this embodiment, theprimary dielectric layer 78 is disposed between the conductive layer 80and the gasket layer 82. A secondary dielectric layer 84 may be providedon top of the conductive layer 80 with the conductive layer 80 beingbetween the primary and secondary dielectric layers 78, 84.

As depicted in FIGS. 10 and 11, the conductive layer 80 has a coveredsurface region 86 and an exposed planar surface region 88. The exposedplanar surface region 88 is lacking a dielectric coating disposedthereon. As depicted in FIG. 9, the primary dielectric layer 78 includesan adhesive coating 90 disposed between the primary dielectric layer 78and the covered surface region 86.

In further detail, the primary dielectric layer 78 has first and secondprimary dielectric layer sides 92, 94. The conductive layer 80 has firstand second conductive layer sides 96, 98. The adhesive coating 90 isdisposed at the second primary dielectric layer side 94. This allows thesecond primary dielectric layer side 94 to be attached to the firstconductive layer side 96. The gasket layer 82 includes first and secondadhesive gasket layer sides 100, 102. The gasket layer 82 furtherincludes a gasket opening 104 disposed through the gasket layer 82. Thefirst primary dielectric layer side 92 is attached to the secondadhesive gasket layer side 102. The secondary dielectric layer 84 hasfirst and second sides 106, 108. As depicted in FIG. 11, the secondarydielectric layer 84 may include an adhesive coating 110 between thesecondary dielectric layer 84 and the conductive layer 80. This allowsthe first side 106 to be attached to the second conductive layer side98.

According to various embodiments, the exposed planar surface region 88may be parallel to but extends beyond the gasket layer 82, such asdepicted in FIGS. 10 and 11. For example, the exposed planar surfaceregion 88 may extend beyond the gasket layer 82 by at least 1millimeter.

The exposed planar surface region 88 provides a contact for anelectrical connection to the conductive layer 80. During the peelingaction of the removal process of the seal 76 from the disk drive base18, a grounded person (e.g. factory worker) or tool (not shown) can beutilized to make electrical contact with the exposed planar surfaceregion 88 to allow the mobile charges (negative charges in this example)to be drained away to ground. Such a grounded tool may take the form ofconductive metal tweezers that are connected to an electrical ground.The exposed planar surface region 88 does not have any adhesive upon itand is disposed towards the disk drive base 18. This would convenientlyallow such tooling as tweezers to engage the seal 76 by pinching thetab-like portion of the seal 76 about the second secondary dielectriclayer side 108 and the first conductive layer side 96 at the exposedplanar surface region 88. While the exposed planar surface region 88 isformed as a tab-like portion of the seal 76, the exposed planar surfaceregion 88 may be of a variety of shapes, geometries and locations.

The primary dielectric layer 78, the conductive layer 80, the secondarydielectric layer 84, and the gasket layer 82 may have a variety ofshapes, sizes, thicknesses and geometries and may be formed of a varietyof materials such as the primary dielectric layer 42, the conductivelayer 40, the secondary dielectric layer 66, and the gasket layer 44 asdiscussed above.

What is claimed is:
 1. A disk drive comprising: a disk drive housingincluding a hole therethrough; a disk enclosed within the disk drivehousing, the disk being rotatably attached to the disk drive housing;and a seal covering the hole through the disk drive housing, the sealcomprising a conductive layer having a covered surface region and anexposed planar surface region, the exposed planar surface region lackinga dielectric coating disposed thereon; a primary dielectric layerincluding an adhesive coating disposed between the primary dielectriclayer and the covered surface region; and a gasket layer including afirst adhesive gasket layer side and a gasket opening disposed throughthe gasket layer, the gasket opening disposed about the hole in the diskdrive housing with the first adhesive gasket layer attached to the diskdrive housing.
 2. The disk drive of claim 1 wherein the conductive layeris disposed between the primary dielectric layer and the gasket layer.3. The disk drive of claim 2 wherein the primary dielectric layer has aprimary dielectric layer opening, and the exposed planar surface regionis aligned within the primary dielectric layer opening.
 4. The diskdrive of claim 3 wherein the primary dielectric layer opening is a holethrough the primary dielectric layer.
 5. The disk drive of claim 3wherein the primary dielectric layer has a plurality of primarydielectric layer openings, and the exposed planar surface regioncomprises a plurality of sections with respective ones of the sectionsbeing aligned within the primary dielectric layer openings.
 6. The diskdrive of claim 1 wherein the conductive layer comprises an aluminummaterial.
 7. The disk drive of claim 1 wherein the primary dielectriclayer comprises a polymer material.
 8. The disk drive of claim 1 whereinthe gasket layer comprises a laminated adhesive material.